Tree Crickets of the Continental U.S.

http://www.wisentsoc.org/wp-content/uploads/2018/02/Key-for-Tree-Crickets-encountered-in-U.S..pdf

There are 18 regularly encountered tree cricket species in the continental U.S. (17 in the genus Oecanthus; 1 in the genus Neoxabea). Additionally, there are two species documented in the 1900's that have not since been encountered: Neoxabea Formosa and Oecanthus leptogrammus.

In the continental U.S. there are 4 species groups in the genus of Oecanthus (species with similar characters):
nigricornis (8 species): Pine, Tamarack, Four-spotted, Prairie, Fast-calling, Walker's, Forbes' and Black-horned.
niveus (3 species): Narrow-winged, Davis', Thin-lined
rileyi (2 species): Snowy, Riley's

varicornis (4 species): Different-horned, Texas, Western and Broad-winged

There are only two Neoxabea species known from the U.S.: Two-spotted and Brownsville.

Tree crickets are often difficult to ID from photographs. Some species have unique characters which are instantly able to be ID'd. Narrow-winged have a ' J ' mark on the 1st segment of the antennae. Broad-winged tree crickets have bright raspberry red on the head and extending up into the antennae.

There are several species, however, that look remarkably similar. If the antennal markings are not visible in the photo, mistakes can be made. Prairie can be confused with Forbes' or Four-spotted; Forbes' can be confused with Black-horned; Tamarack can be confused with Pine; Texas can be confused with Different-horned; Snowy can be confused with Riley's; and Narrow-winged can be confused with Davis'.

A good way to distinguish some species is by the pulse rate of the male's song. These pulses can be counted on a waveform from recordings. One must know the ambient temperature at the spot where the male was singing. Graphs are then used to plot the pulse rate at a known temperature. Dr. Thomas J. Walker created graphs which can help determine species within the nigricornis group: http://entomology.ifas.ufl.edu/walker/buzz/s576lw63.pdf

Links for more info about tree crickets:

http://entomology.ifas.ufl.edu/walker/buzz/s576a.htm
http://orthoptera.speciesfile.org/Common/basic/Taxa.aspx?TaxonNameID=1128056
www.oecanthinae.com less ↑